Manufacture of sheet material



- Patented Sept. 29, i931 UNITED STATES omen I 1mm; 2, nose; or .uoxson smears, sawyou, sssxexon, 'ro GENIBAL'BUBBIB collrm, or m roux, 1w. Y., acumen-non or maw mm! nmsoruna or sun naraam 10 Drawing.

This invention relates to improvements in the manufacture of fibrous sheet material forming the product into sheets or slabs.

according to the customary methods of manufacture. I The bitumino'usdispersions may be prepared in any desired manner, as for example an asphalt in a non-solvent y dispersing thereo pre erably water, in the presence of a protective colloid, using any of the machinery or apparatus customarily em ployed in the -manufacture of. emulsions, suspenslons or dlspersions. The mventlon' is not limited to any particular method of manufacturing the dispersions. above men tioned, but Iprefer that the bituminous material shall be dispersed with a protective as. I believethat t e bituminous particles are more firmly attached to the fibres .when such a protective a' nt is'hsed than'is the case when collo'ida clays are used as the protective agent. 1 e

As one illustration of a method of carryin out-the invention, a paper making fibre isieaten in water in the usual way custom- I ary in the manufacture of paper. -When the beat' operation has beencarried to a suficienii ggreeofor the ,pre Motion of the desired sheet, the beatera'o '.is raised and a water dispersion of- ,.rubberf preferably latex) and a water dispereionofv itimiinou's Such 4 prodssess a high v change from a clomhv a ent such as a soa forexam 1e rosin soa g i] a rial are added to the]beaterin anyde-. sired percentages whilethe in.

Application fl led-pecember 2, 1926. Serial No. 158,813.

continued in operation, thus operating to bring about a uniform distribution of the pAafper pulp, rubber and asphalt dispersions.

er a uniform distribution is obtained, the

rubber and asphalt contents of the beater are precipitated or COfigllltltGdggFOll the paper rooess lution is preferably of a 3-5% concentration and while it is being added to the beater the roll is preferably continued in 0 ma tion to produce a thorough mixing 0' the beater contents and to obtain such a distribution'that the coagulation will go on uniformly throughout the whole mess without j being localized so that itwill be easily apparent when complete. coagulation or deposition of therubber and asphalt on the beaten fibres has taken place because at that point the water content of the beater will mass to a conditionin vwhich the pulp an adhering asphalt and rubber can clearly be seen as dispersed in afsubstantially clear water showing quan titative retention on the fibres of the entire contentsof dispersed materials. Of course it is understood that the total amount 0 rubber and bituminous material compa with the fibre contentsof the beater may bevaried within wide ra es,.but a good practice is to add a total 0 20-50% 0 the rubber and asphalt dispersion compared with the dry weight of the fibre. And of course it is understood that the" roportion' of bituminous material to the rub r may be e varied .within. wide limits .as for example,

5-100% of asphalti com ared with the V n o amount of rubber. arypractice I have founda' very usefulroduct to be obtained by the use of equa parts of rubber andasphalt.@

The treated fibrejs may now be passed to the stuff chests and to the paper making machine and further handled in accordance with ordinary pa r'making "Instead'of the 'regoingmethod'of introducing the rubber and asphalt dispersions, I may introduce the rubber dispersion first and coagulate and deposit the rubber dispersion on the fibre alone. After the rubber has been deposited by the coa ation process upon the fibre as Just descri d, the contents of the beater are made slightly alkaline with caustic soda, ammonia or other suitable alkali. The as halt dispersion may now be added and a er thorough mixing with the beater contents is deposited by coagulation on the fibre by the addition of a further quantity of coagulatin material which is preferably added in su ficient quantity to render the contents of the beater appreciably acid in reaction. Of course the procedure immediately above described may be varied by varying the order of addition of the dispersed materials by adding the asphalt dispersion first and then subsequently adding the rubber dispersion.

Sheets containing rubber and asphalt, when prepared as above described, differ widely from sheets containing rubber and asphalt, but made in different ways. The

' products of this invention have much more pliability than the as halt-containing sheets heretofore known. urthermore, the products of the invention are characterized by much greater initial resistance to tear, as

well as a greater actual tear resistance, and by a greater degree of stretch, than is found in latex papers or in asphalt sheet materials. These properties are extremely useful in the arts. The rubber and as halt are intimatebres prior to the sheet forming operation, and the products of the invention are therefore diiierent from other. sheet materials containing the same ingredients, but where the ingredients are mechanically held by the sheet, as for exmoldability, as demonstrated by the sharpample when the materials are introduced P after the sheet is formed, or when the dispersed materials are not coagulated.

By way of illustration fibrous sheet materials containing rubber and bitumen, prepared as above described, are very satisfactory for use as backing materials for imitation leather, for example automobile toppings, lup' age, upholstery, book covers, etc. Certain c aracteristic properties of the product of this invention are of extreme usefulness in the above instances. The prodnets are characterized by a high degree of ness and permanency of embossed impressions made upon the sheet. Another property is pliability, demonstrated by the ease with which the sheet material may be manipulated for covering the tops and lining the interiors of automobiles, and for general upholstery purposes. The high stretch of the fibrous sheet permits the material to be pulled around and over corners and edges without *fiermaticn oi wrinkles.

Thick sheets of the above described material may. be used very satisfactorily for the manufacture of box toes and counters for footwear. The above described properties of moldability, pliability and stretch are valuable assets in the manufacture of these and other shoe parts. In this instance a selection of the type of bitumen may be made so that the resultinglproduct is thermo plastic, can be molded w ile hot, and after cooling will assume the necessary rigidity required by the footwear industry for box toes and counters. i In addition to the above mentioned properties which are characteris tic of the materials of this invention, there is a very high initial resistance tov tear when attempts are made to tear an edge of the matenal. This is due to the comparatively high stretch of the product and this property makes it extremely valuable as a stay material or reinforcing material for shoes.

By carefully selecting the fibre, and beating it so as to obtain a short length and high degree of hydration and then incorporating the rubber and bitumen as above described, thick slabs can be made. These thick products show a high resistance to abrasion. and great flexibility, and at the same time the slabs are moldable and capable of holding stitches. These thick slabs may be used as outsoles, midsoles, or inner soles for footwear. .One satisfactory Way of preparing these heavier products is to run the fibre and dispersed material on a standard wet machine. Similar products may be made by first partially removing the water content of the fibre mixture, for example by draining and pressing, and subsequently molding the partially dried fibre in a plunger mold, or by other suitable means, including hydraulic or mechanical resses.

Paper and-fibrous sheet material made according to the present invention are more resistant to water than either latex paper or asphalt papers and sheets. Combinations of beaten fibre, dispersed rubber and bituminous material made by the herein-described methods possess the property of running smoothly on paper-making machinery, and the bituminous material does not stick to the Wires, felts or rolls, as has always been the case 1n the prior manufacture of sheet material containing such material, but prepared in other ways.

On account of the molding properties of this material the ulp after deposition or" the rubber and asp alt may be molded into articles without first making the sheet. this instance it is preferable, although not necessary, to'remove all of the water from the pulp before the molding operation.

The invention contemplates the use of rubber in any of its dispersions, natural, synthetic or artificial, or mixtures of an of these. The rubber itself may comprise the globular rubber particles occurring in natural latex, or it may be an artificial latex comprising dispersed crude rubber, vulcanized rubber, reclaimed rubber separately may comprise the natural asphalts, earth waxes or -mineral waxes, as well as the other mineral pitches, resins, tars, tar residues, condensatlon products, etc.

If desired, the asphalt dispersion may likewise be compounded in somewhat the same fashion as the rubber dispersion may be mixed with other ingredients.

In View of the latitude which is permissible in the selection of materials forming the internal phase of the dispersions, the terms rubber dispersion and dispersion of reinforcing material as used in the appended claims are to be broadly construed as including the materials herein described as well as their equivalents. The term sheet material as used in the appended claims is to be construed as generic to any of the fibrous products resulting from paper making methods and machinery, and includes slabs of varying thicknesses and paper.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. Process for making fibrous sheet material which comprises beating paper-making pulp, introducing rubber dispersion and bituminous dispersion into the beaten pulp, coagulating the solid material from both dispersions on the pulp, and recovering the treated pulp. 2. Process for making fibrous sheet material which comprises beating paper-making fibre, separately adding rubber and bituminous material in dispersed form, mixing the dispersions with'the fibre, and coagulating the solid material on the fibres, and subse quently forming the treated fibres into sheets.

3. Process for' making fibrous sheet material which comprises beating paper-making fibre, adding a rubber dispersion to the beater? pulp, mixing said dispersion with the beaten fibre, adding suflicient coagulant to deposit the dispersion on the fibres, introducing a dispersion of bituminous material before the rubber dis ersion-is completely coagulated, and comp eting the coagulation of both dispersions, and forming into sheets.

4:. Process for makin sheet material which comprises beating'fi re, adding a rubber dispersion to the eaten fibre, mixing said dispersion with the beaten fibre, slowly and continuously coagulating the dispersion 0n the fibres, introducing a dispersion of bituminous material before the rubber dispersion is completely coa ulated, and completing the coagulation 0 both dispersions, and forming into sheets.

5. Process for making sheet material which comprises beating paper-making fibres, adding a rubber dispersion to the contents of the heater in the presence of alkali, neutralizing the contents of the heater to deposit the rubber on the fibre, introducing further quantities of alkali into the mixture, adding a dispersion of bituminous material, acidifying the resulting mixture and depositing both rubber and bltuminous material on the fibres, and subsequently forming the latter into sheets.

'6. Process for makingfibre sheets which comprises beating paper-making fibre, addv ing rubber dispersion thereinto in the presence of an alkali, neutralizing the alkali, mixing to distribute the rubber throughout the fibre, introducing a further quantity of alkali, adding an asphalt emulsion to the beaten pulp, acidifyin the mixture to deposit both rubber an asphalt u on the fibres, and subsequently forming t e latter into sheets.

7. Process for making fibrous sheet mate rial which comprises beating paper-making fibres, introducing dispersed rubber and bituminous material into the beaten fibres, 00- agulating the rubber and bituminous material on the fibres, and forming the treated fibres into sheets.

8. As a new product, fibrous sheet material comprising beaten fibres and rubber and bituminous material, the fibres of said product having the characteristics of having been coated with said rubber and bituminous material by coagulation of said rubber and bituminous material from a water dispersion thereof on said fibres in a pulp suspension of the fibres. c

Signed at New York, county and State of New York, this 26th day of November, 1926.

. 7 REED P. ROSE. 12 

